<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        .flex {
            display: flex;
            justify-content: space-between;
            align-items: center;
        }
        .div1{
            /* flex: 1; */
        }   
        .div2{
            /* flex: 2; */
        }   
        .div3{
            /* flex: 3; */
        }   
        .div4{
            /* flex: 4; */
        }   
    </style>
</head>
<body>
    <div class="flex">
        <div class="div1">1</div>
        <div class="div2">2</div>
        <div class="div3">3</div>
        <div class="div4">4</div>
    </div>
</body>
</html>